CORE B: CANINE HISTOCOMPATIBILITY TYPING The Canine Histocompatibility Typing Core is designed to meet the needs of the two canine research Projects 1 and 2 on this Program Project Grant. The Core personnel consist of a Core Director, a Staff Scientist, and one technician. The primary role of the service consists of canine histocompatibility typing to identify Dog Leukocyte Antigen (DLA)-identical littermate pairs for hematopoietic cell transplantation and to select pairs of dogs with desired histocompatibility type for breeding. These efforts are critical in order for the dog to function as a translational model for human hematopoietic cell transplantation. While the typing effort is focused on the two most polymorphic class I and class II loci, DLA-88 and DRB1, additional efforts will involve developing methods for typing 3 additional polyallelic DLAclass I loci. This Core will also generate dendritic cells, develop genetically modified K562 cell lines for expression of selected DLA class I alleles, and develop tetramers for minor antigen-specific T cell identification and characterization.